I have a 2010 F150 crew cab, the gas gauge is so inaccurate it's unreal. My Ford dealer had almost replace everything in the system, now per fords service tects they are to replace the fuel tank. They say it "could" be because the tank sucks in when driving, Of course the tank is some kind of plastic. The last time I filled it up it showed 1/3 tank and took 3 gals. Which won't take you very far.

 

Mine is in the shop also for fuel gauge issue not reading full when I fill it up.